The stately fortress, also called Branzoll Castle, characterises the townscape more than practically any other building. The massive square keep with its pyramidal roof, the attached residential buildings and, last but not least, the fluttering red and white Tyrolean flag are all unmistakably part of Klausen. The castle is privately owned and therefore cannot be visited.

Construction dates back to 1255: constant power struggles with the Bishop of Brixen led the influential and noble lords of Säben to build Branzoll Castle below the monastery in order to control access to Säben. The bishops ultimately succeeded in the conflict and took possession the castle: they appointed a keeper there, whose task was to manage and if need be to defend it.

In 1533 a fire destroyed the bishop’s castle on Säben, rendering it uninhabitable. The residence of the castle governor was therefore moved to Branzoll Castle. Branzoll itself fell victim to fire 150 years later: only the outer walls of the tower remained, looming as ruins over the town. However, as falling masonry threatened the houses of the old town, shortly before 1900 the bishop’s curia donated the ruins to the municipality of Klausen. The town in turn found an interested buyer in the art collector and castle enthusiast Dr Karl Traut from Innsbruck. He built a new residential wing as an extension to the historic tower and, with a fine sense for the artistic, turned the new building into a magnificent residence that is just as impressive as a genuine medieval castle.